Biology Module 1 Quiz/Homework Practice
Terms in this set (42)
The original source of all genetic variation is _____.
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.
What situation most likely explains the occasional high frequency of certain inherited disorders among human populations established by a small population?
The evolutionary effects of genetic drift are greatest when _____.
The population size is small.
In evolutionary terms, an organism's fitness is measured by its _____.
Contribution to the gene pool of the next generation.
For 1981, 1987, and 1990, how does the frequency of left-mouthed breeding adults compare to the frequency of left-mouthed individuals in the entire population?
Most of the breeding adults had the opposite phenotype of that which was most common in the population.
What do these comparisons suggest about when natural selection favored left-mouthed individuals over right-mouthed individuals?
Left-mouthed individuals were selected for when right-mouthed individuals were more common, and vice versa.
Natural selection changes allele frequencies because some _______ survive and reproduce more successfully than others.
If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus?
gene variability = 0%; number of alleles = 1
There are 40 individuals in population 1, all with genotype A1A1, and there are 25 individuals in population 2, all with genotype A2A2. Assume that these populations are located far from each other and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation is most likely an example of
Researchers studied genetic variation in the marine mussel Mytilus edulis around Long Island, New York. They measured the frequency of a particular allele (lap94 ) for an enzyme involved in regulating the mussel's internal saltwater balance. The researchers presented their data as a series of pie charts linked to sampling sites within Long Island Sound, where the salinity is highly variable, and along the coast of the open ocean, where salinity is constant.
How do the data from sites 9-11 compare with the data from the sites within the Sound?
The frequency of the lap94 allele is higher at sites 9-11 than it is within the Sound; however, the northeast edge of the Sound has nearly the same frequency of the lap94 allele as do sites 9-11.
Two observations can be made regarding this study:
1. The lap94 allele helps mussels maintain osmotic balance in water with a high salt concentration, but it is costly to use in less salty water.
2. Mussels produce larvae that can disperse long distances before they settle on rocks and grow into adults.
What hypothesis would explain the patterns in the data?
The frequency of the lap94 allele at different sites results from an interaction between selection and gene flow.
You read about soapberry bugs and select the correct statement describing relative fitness in these individuals.
A soapberry bug with high relative fitness has a relatively high number of offspring that survive to reproductive age.
Which statement correctly describes the role of chance in evolution?
The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA.
Sympatric speciation is _____.
the appearance of a new species in the same area as the parent population
Which of the following has been shown to cause speciation most rapidly?
According to the _____ model, evolution occurs in spurts; species evolve relatively rapidly then remain unchanged for long periods.
Blue poppies native to China were grown at a plant-breeding center in California. The plants with the thickest leaves were most likely to survive and reproduce in the drier climate. After several generations, the percentage of thick-leaved plants had increased by 42%. This adaptation of the poppies to their new environment is due to _____.
How does diploidy help to preserve genetic variation?
It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes.
A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?
The fruit fly Drosophila melanogaster has an allele that confers resistance to DDT and similar insecticides. Laboratory strains of D. melanogaster have been established from flies collected in the wild in the 1930s (before the widespread use of insecticides) and the 1960s (after 20 years of DDT use). Lab strains established in the 1930s have no alleles for DDT resistance. In lab strains established in the 1960s, the frequency of the DDT-resistance allele is 37%. Which statement is correct?
The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread.
Allele frequencies in a gene pool may shift randomly and by chance. What is this random shift called?
Which of the following taxonomic categories contains all the others listed here?
What process actually increases the number of genes in an organism's genome?
Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?
DNA coding for rRNA changes relatively slowly.
Which process occurred frequently in the early history of the three domains on Earth, and makes determining phylogenetic relationships of that time difficult?
Horizontal Gene Transfer
Which observation supports the position of eukaryotes at the convergence of the "ring of life"?
The nuclear genome of eukaryotes contains genes from archaeans and from bacteria.
The nucleic acid of a virus particle is enclosed in a protein coat. What is it called?
What do we call a virus that attacks a bacterium?
Why are viruses called obligate intracellular parasites?
They must use a host cell's amino acids to synthesize proteins.
They must use a host cell's ribosomes to synthesize proteins.
They must use a host cell's nucleotides for transcription and replication.
They must use a host cell's metabolic enzymes and pathways to obtain energy.
What is the most effective way to stop viral infections?
A plant that has been raised in a sterile environment shows symptoms of a viral infection. How would you explain this?
The viral infection was acquired by vertical transmission.
The H1N1 2009 outbreak is considered to have been which of the following?
How do prions, which are misfolded proteins, infect organisms?
Prions enter brain cells and cause normal forms of the protein to refold into the prion form.
Emerging viruses arise by
mutation of existing viruses.
the spread of existing viruses more widely within
their host species.
the spread of existing viruses to new host species.
all of the above
How does a virus differ from a bacterium?
Select all that apply.
Viruses, unlike bacteria, lack metabolic enzymes.
Why is it ineffective to treat viral disease with antibiotics?
Antibiotics inhibit enzymes specific to bacteria and have no effect on virally encoded enzymes.
To cause a human pandemic, the H5N1 avian flu virus would have to
become capable of human-to-human transmission.
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have
T4 Protein and T4 DNA
RNA viruses require their own supply of certain enzymes because
host cells lack enzymes that can replicate the viral genome.
All of the statements below are true. Select the statement that best supports the view of most biologists that viruses are nonliving.
An isolated virus is unable to replicate its genes or regenerate ATP.
Identify all correct statements about how viroids differ from viruses.
Unlike viruses, viroids do not encode proteins.